Abstract : A high-order interpolation procedure is proposed for supplying initial and boundary values in fine-mesh limited-area models. The procedure recognizes and compensates for the fact that low-order interpolation such as linear interpolation has a strong damping effect, particularly on the shorter-wavelength features of the field. Starting with linear interpolation, a general operator of arbitrary order is developed for the purpose of restoring as much of the damped information as possible for any particular order of interpolation without amplifying any spectral component beyond its original value. Numerical simulation experiments in a nested region whose gridspacing is one-fifth that of the coarse grid are performed with an eight-level primitive equation model to compare the solution obtained by means of two-point linear interpolation with the solution obtained by means of the eight-point ideal interpolation operator. (Modified author abstract)